All-terrain wheelchairs and apparatus therefor

Abstract

A lightweight set of attachments adapted to convert a conventional wheelchair to an all-terrain vehicle without compromising the general utility of said wheelchair for everyday use.

I claim: 
     
       1. An all-terrain vehicle, said vehicle comprising, in combination: a wheelchair having a frame, a pair of rearwardly positioned drive wheels one axially mounted to each side of said frame, a seat positioned within said frame substantially between said drive wheels to accommodate the user of said chair, and a pair of small diameter, narrow width steering wheels each positioned on either side of said frame forward of said drive wheels;   detachable load bearing and propulsion extension means adapted to fit against, outward of and just inside the circumference of said drive wheels and provide traction on soft, sandy, loose or uneven surfaces without changing the relative position of the user of said wheelchair to said drive wheels; and   detachable means for supporting said steering wheels without compromising the steering ability of said steering wheels when said vehicle is used on soft, sandy, loose or uneven surfaces.   
     
     
       2. The all-terrain vehicle of claim 1 wherein each of said detachable load bearing propulsion extension means comprises a flexible substantially flat tread portion which connects end-to-end and mounts interior of the circumference to each of said drive wheels to form a continuous load bearing surface terminating along the outer edge in a graspable bulbous portion extending circumferentially and outwardly of each drive wheel which the chair user can grasp to provide a propulsive force for said chair, and a plurality of positioning/attachment means located roughly equidistantly around the inner surface of said flat tread portion between the outer circumference of said drive wheel and said inner surface, said positioning/attachment means comprising means for properly positioning said load bearing and propulsion extension means to said drive wheels and for snugly tightening said load bearing and propulsion extension means into position. 
     
     
       3. The all-terrain vehicle of claim 2 wherein each of said positioning/attachment means comprises a right angled portion which is an inward extension of the flat tread portion, said right angle section being positioned to rest against the outer surface of said drive wheel and act to properly orient the load bearing and propulsion extension means against the drive wheel in combination with a plurality of strap means having one end anchored to said right angled portion and the other end anchored to an angular support means extending inward from said bulbous portion and resting against said drive wheel, a first part of said strap means being passed through the spokes of the drive wheel to make contact with a second part of said strap means and lockingly fasten together to hold the load bearing and propulsion extension means in position. 
     
     
       4. The all-terrain vehicle of claim 3 wherein said said plurality of straps each comprises a pair of hook and loop type fasteners each being mounted onto the opposing surfaces of said first and second parts of said strap means. 
     
     
       5. The all-terrain vehicle of claim 1 wherein said detachable means comprises a pair of rotatable, axially mounted broad auxiliary wheels located on an H-shaped frame secured to each of said steering wheels, said H-shaped frame having a relatively large upwardly opening channel adapted to fit on either side of each steering wheel, said channel provided with a curved plate which spans the gap across the channel between the upright portions of the H-shaped frame, said curved plate positioned so that the broad auxiliary wheel axles will be substantially in line with the axle of each steering wheel. 
     
     
       6. The all-terrain vehicle of claim 5 wherein said H-shaped frame further having a lower section containing at least one small diameter, short steering wheels fitted into said H-shaped frame lower section to lie just below the curved plate and between the broad auxiliary wheels to improve the ability of the user to steer the chair on relatively firm surfaces by reducing the frictional resistance of the front wheels to changing direction when the chair is in motion. 
     
     
       7. The all-terrain vehicle of claim 6 wherein said lower section of said H-shaped frame houses at least three of said short steering wheels positioned one behind the other within said lower H-shaped frame section. 
     
     
       8. The all-terrain vehicle of claim 1 wherein said detachable means comprises a pair of rotatable, axially mounted broad auxiliary wheels located on a U-shaped frame secured to each of said steering wheels and adapted to fit on either side of a steering wheel and support said steering wheel within said U-shaped frame by a cross bar which underlies said steering wheel and spans the gap between the upright portions of the U-shaped frame, said cross bar being positioned so that the broad auxiliary wheel axles will be substantially in line with the axle of each steering wheel. 
     
     
       9. The all-terrain vehicle of claim 8 wherein said broad auxiliary wheels and said steering wheel are mounted on a common axle. 
     
     
       10. The all-terrain vehicle of claim 1 further comprising an anti-tipover means to prevent backward tip beyond a maximum angle from the horizontal plane of the underlying surface attached to the lower side supports of the frame and rearwardly of the axle for the drive wheels, said anti-tipover means being angularly adjustable by a rotatable means attached between said lower side supports of the frame along a telescoping bar spanning the distance between the lower side supports of the frame. 
     
     
       11. The all-terrain vehicle of claim 10 wherein the maximum angle falls within a range not to exceed 35° from the horizontal plane of the underlying surface. 
     
     
       12. The all-terrain vehicle of claim 1 wherein said detachable load bearing and propulsion extension means is made from a group of materials consisting essentially of polymeric or elastomeric material. 
     
     
       13. The all-terrain vehicle of claim 1 wherein said broad auxiliary wheels are made from a foamed polymeric material. 
     
     
       14. An all-terrain attachment for a wheelchair, said wheelchair having a frame comprising a pair of rearwardly positioned drive wheels axially mounted one on either side of said frame for travel over smooth and hard surfaces, a seat positioned within said wheelchair frame positioned substantially over the axle for said drive wheels to accommodate the user of said chair, and a pair of small diameter, narrow width steering wheels each positioned on either side of said frame forward of said drive wheels, said attachment comprising in combination, plural detachable load bearing and propulsion extension means adapted to fit against and outward of and just inside the circumference of said drive wheels and provide traction on soft, sandy, loose or uneven surfaces without changing the relative position of the user of said wheelchair to said drive wheels and further comprising detachable means for supporting said steering wheels without compromising the steering ability of said steering wheels when said vehicle is used on soft, sandy, loose or uneven surfaces. 
     
     
       15. The all-terrain vehicle of claim 14 wherein each of said plural detachable load bearing and propulsion extension means comprises a flexible substantially flat tread portion which connects end-to-end and mounts interior of the circumference of the outermost sides of said drive wheels to form a continuous load bearing surface terminating along the outer edge in a graspable bulbous portion extending circumferentially and outwardly of each drive wheel which the chair user can grasp to provide a propulsive force for said chair, and a plurality of positioning/attachment means located roughly equidistantly around the inner surface of said flat tread portion between the outer circumference of said drive wheel and said inner surface, said positioning/attachment means comprising means for properly positioning said load bearing and propulsion extension means to said drive wheels and for snugly tightening said load bearing and propulsion extension means into position. 
     
     
       16. The all-terrain vehicle of claim 15 wherein each of said positioning/attachment means comprises a right angled portion which is an inward extension of the flat tread portion, said right angle section being positioned to rest against the outer surface of said drive wheel and act to properly orient the load bearing and propulsion extension means against the drive wheel in combination with a plurality of strap means having one end anchored to said right angled portion and the other end anchored to an angular support means extending inward from said bulbous portion and resting against said drive wheel, a first part of said strap means being passed through the spokes of the drive wheel to make contact with a second part of said strap means and lockingly fasten together to hold the load bearing and propulsion extension means in position. 
     
     
       17. The all-terrain vehicle of claim 16 wherein said plurality of straps each comprises a pair of hook and loop fasteners each being mounted onto the opposing surfaces of said first and second parts of said strap means. 
     
     
       18. The all-terrain vehicle of claim 14 wherein said detachable means comprises a pair of rotatable, axially mounted broad auxiliary wheels located on an H-shaped frame secured to each of said steering wheels, said H-shaped frame having a relatively large upwardly opening channel adapted to fit on either side of each steering wheel, said channel provided with a curved plate which spans the gap across the channel between the upright portions of the H-shaped frame, said curved plate positioned so that the broad auxiliary wheel axles will be substantially in line with the axle of each steering wheel. 
     
     
       19. The all-terrain vehicle of claim 18 wherein said H-shaped frame having a lower section containing at least one small diameter, short steering wheels fitted into said H-shaped frame lower section to lie just below the curved plate and between the broad auxiliary wheels to improve the ability of the user to steer the chair on relatively firm surfaces by reducing the frictional resistance of the front wheels to changing direction when the chair is in motion. 
     
     
       20. The all-terrain vehicle of claim 19 wherein said H-shaped frame further comprises a lower section housing at least three of said steering wheels positioned one behind the other within said lower H-shaped frame section. 
     
     
       21. The all-terrain vehicle of claim 14 wherein said detachable means comprises a pair of rotatable, axially mounted broad auxiliary wheels located on a U-shaped frame secured to each of said steering wheels and adapted to fit on either side of a steering wheel and support said steering wheel within said U-shaped frame by a cross bar which underlies said steering wheel and spans the gap between the upright portions of the U-shaped frame, said cross bar being positioned so that the broad auxiliary wheel axles will be substantially in line with the axle of each steering wheel. 
     
     
       22. The all-terrain vehicle of claim 21 wherein said broad auxiliary wheels and said steering wheel are mounted on a common axle. 
     
     
       23. The all-terrain vehicle of claim 14 further comprising an anti-tipover means to prevent backward tip beyond a maximum angle from the horizontal plane of the underlying surface attached to the lower side supports of the frame being and rearwardly of the axle of the drive wheels, said anti-tipover means being angularly adjustable by a rotatable means attached between said lower side supports of the frame along a telescoping bar spanning the distance between the lower side supports of the frame. 
     
     
       24. The all-terrain vehicle of claim 23 wherein said maximum angle falls within a range not to exceed 35° from the horizontal plane of the underlying surface. 
     
     
       25. The all-terrain vehicle of claim 15 wherein said detachable load bearing and propulsion extension means is made from a group of materials consisting essentially of polymeric or elastomeric material. 
     
     
       26. The all-terrain vehicle of claim 15 wherein said broad auxiliary wheels are made from a foamed polymeric material.